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Model specific boards => Golf mk4 => Topic started by: N4SOP on 11 November 2012, 18:20

Title: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: N4SOP on 11 November 2012, 18:20

*I took the GTi for a long run today (100 miles) and noticed the temp gauge sat in the cold sector all the time until I got stuck in some traffic. Then it climbed to 90 degrees and sat there until I moved again, then it fell into the cold sector.

At all times the heaters blew hot air so I'm guessing it the Temp Sender?

I noticed while sat at motorway speeds it seem to hunt a little almost like a very slight missfire. Does the Mk4 Temp Sender do more than just control the gauge? Got a feeling it also talks to the ECU about mixture etc?

Any help would be great :)

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: Granta Gti on 11 November 2012, 18:34

Defo sounds like a thermostat  :smiley:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: rio_gti on 11 November 2012, 18:35

thermostat mate its stuck open do its constgantly flowin thru the rad and alwayd coolin down when on the move  :wink:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: Ant1981 on 11 November 2012, 18:37

If you're constantly blowing hot air, then it's getting hot, so it possible it may not be the thermostat.

If the temp actually were cold, would your blower have any hot air?

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: Granta Gti on 11 November 2012, 18:43

Mine did exactly the same and I thought it blew out hot air until I changed the thermostat and then it was HOT!

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: N4SOP on 11 November 2012, 18:47

Cheers for the replies guys  :smiley:

Is it an easy-ish job to replace the thermostat? Rough cost of one?

My concern was that the gauge never went above 90 degrees, even when stationary in traffic. Didn't want it to overheat it it was a sender fault rather than the thermostat.

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: rio_gti on 11 November 2012, 18:50

never goes over 90- that means your fans are working!!!

about £12 and less than an hour to do  :smiley:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: N4SOP on 11 November 2012, 18:54

Great stuff  :smiley:

I'm coming direct from Vaux ownership so my VW knowledge is a little lacking at the moment!

I'll do the sender first then look at the stat  :smiley:

PS. The fan must be VERY quiet..

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: gm8 on 11 November 2012, 19:00

done mine the other week , heaters go from warm to hot enough to bake bread  :evil: bit fiddly but 30 min job , no need to remove alternator either

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: karls3abo on 12 November 2012, 20:26

Just changed mine :) only thing I will say is the bottom bolt is a paint to get at as the alternator is majorly in the way! A ratchet spanner would be a good idea its a 10mm bolt, Also be careful of the dipstick as I found out it is very very! Fragile I barely touched it and it snapped off lol, now  I temporarily have a silicone hose to hold my stick haha. But it's now much hotter! Lovely in the mornings

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: Nino on 13 November 2012, 08:50

Same happened to mine a few months back, MAKE sure u use correct OEM part DO NOT buy euro crap parts they dont last and u will need to do it again in a few months. Also worth changing the Temp sensor if u have noticed your MPG is alittle strange.

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: N4SOP on 08 December 2012, 15:51

Update.

I had the thermostat replaced on Thursday and now have a fully working cooling system. MPG has gone up slightly so I guess it was over fueling a little with it always being cold.

Total cost for replacement £60 inc labour as I didn't want to get cold lol.

Thanks for all the help guys :)

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: GTi_James on 09 December 2012, 10:09

any how to guide on this as i think mines read for retirement  :undecided:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: karls3abo on 09 December 2012, 10:42

Just one other thing I will add to this.  I bought one of the cheapy thermostats on eBay. Something like 13.99 or close to that. Which comes with the housing also,put it on and it worked fine for 2 weeks then suddenly it over heated! Took it to a garage who thought it was the heater matrix and tried flushing it with no luck.. So it played on my mind why some pipes were still cold, then decided to take the thermostat out to test it. Got the housing off and saw that the piston in the middle of the stat was not in its hole causing it not to open.

Problem solved. Don't buy cheap! I regret that now!

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: gm8 on 09 December 2012, 16:55

they are cheap though ? mine was about £8 from GSF (no new housing though)

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: Steve_PD on 09 December 2012, 17:14

Quote from: GTi_James on 09 December 2012, 10:09

any how to guide on this as i think mines read for retirement  :undecided:

Yes in the maintenance section along with many other guides.... :tongue: :whistle:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: karls3abo on 09 December 2012, 19:27

Ye the one I bought was with the o ring and new housing. But obviously the one they were selling was not oem quality.

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: GTi_James on 10 December 2012, 08:57

Quote from: Steve_PD on 09 December 2012, 17:14

Quote from: GTi_James on 09 December 2012, 10:09

any how to guide on this as i think mines read for retirement  :undecided:

Yes in the maintenance section along with many other guides.... :tongue: :whistle:

did a search there mate but think i may of missed then  :sad:

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: gm8 on 10 December 2012, 11:56

http://www.golfgtiforum.co.uk/index.php?topic=101783.0

Title: Re: Temp gauge sits around cold while driving then climbs to 90 degrees when statina
Post by: GTi_James on 10 December 2012, 12:13

thanks mate   :smiley: